The storm devastated the Gulf Coast in 2005, killing thousands and causing billions of dollars of property losses. In the wake of the hurricane, the federal government provided $1 billion to homeowners in Louisiana to raise their homes to prevent future flood damage, ABC News notes.

However, HUD now says it cannot determine what happened to 70% of that money. The agency is asking Louisiana to attempt to recover some of the missing funds.

According to the report, 24,000 homeowners in the state who received grants of $30,000 could not document the required repairs. HUD’s inspector general said that blame for the missing funds belongs both to the state of Louisiana, which failed to properly monitor the program, and homeowners who used the money for other reasons.

Louisiana officials say that efforts are under way to recover missing funds and compel homeowners who accepted grants to make the required repairs.